In a conventional piezoelectric actuator device, a driver including a lower electrode layer, a piezoelectric layer formed on the lower electrode layer, and an upper electrode layer formed on the piezoelectric layer is provided on a vibrator.
Upon having an electric field between the lower electrode layer and the upper electrode layer, the piezoelectric layer expands and shrinks in a surface direction, and bends the vibrator in its thickness direction. This piezoelectric actuator device is employed in a variety of applications, such as a mechanical switch device, a variable capacitance element, a photon scanning device (e.g. barcode reader), and a tuning-fork device used in an angular velocity sensor.
The conventional actuator device is disclosed, for instance, in Patent Literature 1.